Instabilities in a magneto-optical trap: Noise-induced dynamics in an atomic system

The instabilities observed in the atomic cloud of a magneto-optical trap ar e experimentally studied through the dynamics of the center of mass locatio n and the cloud population. Two dynamical components are identified: a slow , stochastic one affects both variables, and a fast, deterministic one affe cts only the center of mass location. A one-dimensional stochastic model ta king into account the shadow effect is developed from these observations an d reproduces the experimental behavior. It is shown that instabilities are driven by noise and present stochastic resonancelike characteristics.